The present invention herein resides in the art of defense systems for diverting the trajectory of incoming missiles. More particularly, the present invention relates to a system which provides simultaneous tracking and identification/classification functions with an infrared receiver having a focal plane array. Specifically, the present invention relates to a system which provides variable imaging rates to detect, jam and divert an incoming infrared missile.
To protect and defend military platforms, such as ships, aircraft, and ground-based installations, it is known to provide countermeasure systems that detect incoming threats such as enemy aircraft or missiles. Known systems detect incoming threats, such as infrared missiles, and then deploy defensive countermeasures in an attempt to destroy or divert the threat. These systems are referred to as open-loop systems since no immediate determination as to the type of threat or effectiveness of the countermeasure is readily available. Due to the inefficiency of the open-loop systems, closed-loop systems have been developed.
There are known performance benefits to using a directional, laser-based, closed-loop infrared countermeasure system to defeat infrared missiles. In a closed-loop system, the incoming missile is identified and the countermeasure system generates or tunes a jam code according to the specific incoming missile. The optimized jam code is directed at the missile which executes a maximum turn-away from its intended target. An additional feature of closed-loop techniques is the ability to monitor the classification and identification process during the jamming sequence. This provides a direct observation of the countermeasure effectiveness as well as an indication of the necessary corrective action required for the jam code. It will be appreciated that the benefits of the closed-loop performance system must be balanced against the cost of upgrading existing infrared directional countermeasure systems with a closed-loop capability, or against the cost of developing an entirely new closed-loop system.
One possible configuration for introducing a closed-loop receiver into a directional countermeasure system is to use a high resolution tracking sensor side-by-side with an infrared detector assembly. Accordingly, an independent receive channel, which is a separate optical path, must be added to the detection system with a separate expensive cooled detector. The cost and size impact of such a configuration to the countermeasure system is prohibitive.
Another approach is to incorporate an infrared detector assembly into the countermeasure system and split a portion of the received optical path for the high resolution tracking sensor. Unfortunately, this approach causes at least a 50% receive loss for both the track sensor and the receiver, plus the cost for adding another cryogenically cooled detector. Another problem with this approach is that the apertures of the sensor and the receiver may not match which would require a larger overall assembly to accommodate both.
Based upon the foregoing, it is apparent that there is a need in the art for a single imaging infrared receiver having a focal plane array capable of sufficient frame rates to provide sensor data for three primary closed-loop countermeasure functions. The receiver must have a passive high resolution tracking capability, it must be able to receive and process laser signals, and finally, the receiver must be able to perform countermeasure effectiveness measurements.
In light of the foregoing, it is a first aspect of the present invention to provide a closed-loop infrared countermeasure system using a high frame rate infrared receiver.
Another aspect of the present invention is to provide a countermeasure system with a missile warning system that detects the presence of an object that may be considered a threat to a platform upon which the system is associated.
Yet another aspect of the present invention, as set forth above, is to provide a countermeasure processor, in communication with the warning system, which coordinates all of the functions and processing of the closed-loop system.
Yet another aspect of the present invention, as set forth above, is to provide a track processor which receives a trajectory signal representative of the missile path from the countermeasure processor based upon the communication received from the warning system to generate a trajectory pointer signal.
Yet a further aspect of the present invention, as set forth above, is to provide a pointer which positions itself based upon signals received from the countermeasure processor and the track processor.
Still a further aspect of the present invention, as set forth above, is to provide an infrared receiver positioned by the pointer, wherein the infrared receiver has an infrared focal plane array that functions simultaneously as a laser receiver and a high resolution track sensor or camera.
Still a further aspect of the present invention, as set forth above, is to provide a laser carried by the pointer, which is bore-sighted with the infrared receiver, which receives instructional signals and commands from the countermeasure processor, wherein a laser beam generated by the laser is initially directed toward the incoming missile threat and obtains operational characteristics therefrom which are received by the infrared receiver, which in turn are transmitted to the countermeasure processor which generates a jam code that is included with the laser beam impinging upon the incoming missile.
Still an additional aspect of the present invention, as set forth above, is to instruct the focal plane array to initiate variable imaging rates, in particular, a first imaging rate is employed to initially acquire and track the incoming threat, a faster second imaging rate is employed to provide a high resolution tracking of the incoming threat and an even faster third imaging rate is employed to obtain operational characteristics of the incoming missile.
The foregoing and other aspects of the present invention, which shall become apparent as the detailed description proceeds, are achieved by a missile tracking and deflection system for protecting a platform, comprising a missile warning system for detecting the presence of a missile and generating a warning signal, a countermeasure processor for receiving the warning signal and generating a warning report, a track processor for receiving the warning report and generating a pointer trajectory signal, a pointer for receiving the pointer trajectory signal to position the pointer toward the missile, a receiver carried by the pointer to receive a passive signature of the missile and generate a trajectory characteristic signal received by the track processor for updating the pointer trajectory signal, and a laser carried by the pointer which directs a laser beam at the missile to generate an active signature received by the receiver which generates a missile characteristic signal received by the countermeasure processor to identify the missile and generate a jam code carried by the laser beam to divert the trajectory of the missile away from the platform, the receiver observing the passive and active signatures, and generating the trajectory characteristic signal and the missile characteristic signal simultaneously.
Other aspects of the present invention are attained by a method for diverting the trajectory of a missile, comprising the steps of detecting the presence of a missile and generating a warning signal, analyzing characteristics of the warning signal with a countermeasure processor which generates a trajectory signal, processing the trajectory signal to generate a trajectory pointer signal, receiving the pointer signal in a receiver which has a single focal plane array that tracks the trajectory of the missile and detects operational characteristics of the missile, the receiver delivering a signal to the countermeasure processor which generates a jam code employed to divert the trajectory of the missile.
Still other aspects of the present invention are attained by an object tracking system comprising a receiver for observing the object, the receiver having a focal plane array for obtaining information about the object, and a processor in communication with the receiver, the processor imaging the focal plane array over at least two frame rates, wherein a first frame rate images a large portion of the focal plane array to observe the object, and a second frame rate, faster than the first frame rate, images a smaller portion of the focal plane array to track the object.